Planet, the Postal Alpha Numeric Encoding Technique barcode is used by the United States Postal Service to identify and track pieces of mail during delivery - the Post Office's "CONFIRM" services.*

Planet symbols encode 12 or 14 digits only, where the last digit is a check digit, automatically calculated by Labeljoy. Therefore, only 11 or 13 digits can be entered.

There is no human readable text displayed with this type of symbology.

Planet encoding 11 digits + check digit
Planet encoding 13 digits + check digit

Text concatenation:
When a Planet barcode element is generated by concatenating fields or counters, the following rules apply:
- Digits only are allowed.
- Only texts of 11 or 13 digits will be considered.
When a value not complying with the above rules is found, the barcode is not displayed.

* From wikipedia.